Roslyn tries to call FailFast from bad expression in Immediate Window

[AArnott]

Version Used: 15.9.2 Preview 1.0 (28307.108.d15.9)

Steps to Reproduce:

1. While stepping in a C# program, type this into the VS Immediate Window and hit enter:

(bool)(object)null

Expected Behavior:

Some error about null not being convertible to bool.

Actual Behavior:

Evaluation of method <Unknown Method>() calls into native method System.Environment.FailFast(). Evaluation of native methods in this context is not supported.

[jinujoseph]

cc @tmat